With the rapid growth in mobile/wireless and other electronics devices, the battery life becomes an important factor in the success of such devices. At the same time, many advanced applications for these devices are becoming more and more popular. Such applications normally require high performance of components in the devices. Sustainable power is limited by the dissipation capability and thermal constraint. The device or semiconductor chips can malfunction if the temperature is too high. Thermal throttle methods are commonly used in the devices to prevent overheat problems due to the dissipation limitation. The traditional thermal throttling unnecessarily sacrifices the performance in order to maintain the temperature with the target temperature. In the traditional way, the device monitors the temperature and triggers power reduction if the temperature becomes higher than a threshold. If the power reduction is too fast, it results in noticeable performance degradation and affects overall device performance. The performance is limited by the sustainable power. If the power reduction is too slow, the temperature continues to rise before it goes down. Overheating will cause shortened lifespan of the chips or even cause permanent damage to the device.
Further, there are multiple ways to control the temperature, including Dynamic Voltage and Frequency Scaling (DVFS), CPU hot-plug, and task migration/cluster switch. In the current system, a single control policy controls different temperature methods. The single policy may fit one method but does not fit others. It results in reduced efficiency and/or sacrifice the system performance.
Furthermore, for each control technique, based on different user preferences and different operating scenarios, the control parameters vary as well. The single policy for all control techniques under any scenarios does not provide the most efficient way in many occasions.
Improvements and enhancements are needed for adaptive optimization for low power strategies.